References
1. Yamada T, Doppalapudi H, McElderry HT, Okada T, Murakami Y, Inden Y, et al. Electrocardiographic and electrophysiological characteristics in idiopathic ventricular arrhythmias originating from the papillary muscles in the left ventricle: relevance for catheter ablation. Circ Arrhythm Electrophysiol. 2010;3:324-331.